Head-mounted display attachment device

ABSTRACT

A head-mounted display and accessory system in which the accessory emits bleaching light through the head-mounted display to bleach photoreceptors for dark adaptation testing includes a casing, where a lens of a head-mounted display is positioned inside the cavity, and where an aperture of the casing is aligned with an exterior-facing camera of the head-mounted display. The system also includes an attachment body, where a posterior end of the attachment body is fixed to an anterior end of the casing, and where the attachment body includes a set of light-emitting diodes (LEDs), where the set of LEDs is attached to the posterior end of the attachment body and is directed towards the lens. The system also includes a circuitry that is configured to control light emission of the set of LEDs.

BACKGROUND

Head-mounted displays are useful for various types of health-relatedtesting, such as dark adaptation testing and another eye-relatedtesting. Such testing provides data that is useful for determiningeye-related conditions. During a dark adaptation test, photoreceptors ofan eye are stimulated through one or more cycles of exposing an eye todarkened or illuminated conditions. The readings acquired during such atest may be used to diagnose eye-related information (e.g., age-relatedmacular degeneration) and other types of health information, such asblood glucose.

SUMMARY

A head-mounted display (HMD) device may measure eye responses during adark adaptation test or other tests that involve exposing an eye todifferent stimuli. Measured physiological changes may be paired withuser-provided inputs that indicate when a user has detected a targetstimulus. Despite the advantages that an HMD can provide to eye-relatedtesting, however, hardware limitations prevent typical HMDs from beingused for certain types of tests, such as dark adaptation testing. Forexample, because general-purpose HMDs are designed for eye comfortover-long user sessions, these HMDs are not configured to provide theintensity of light needed to bleach retinas as required during darkadaptation testing. Furthermore, while bleaching light is a necessarycomponent of many tests, conventional tests may fail to account for usererrors or program errors that may over-expose a user to bleaching light.Such overexposure may lead to discomfort and long-term eye damage. Inaddition, attachments to an HMD may cover up one or more HMD cameras,inhibiting positioning operations reliant on visual data provided by theHMD cameras.

Some embodiments may overcome this technical problem by using a darkadaptation accessory configured to be attached to an HMD (e.g., awearable dark adaptation attachment configured to be mounted over one ormore transparent lenses of the HMD). The accessory device may be capableof exposing an eye to bleaching light while being compatible with ahead-mounted display capable of displaying stimuli and measuringeye-related information. The accessory device may include a light shieldcasing shaped to encompass at least the lenses of a head-mounteddisplay, where the light shield casing is designed to shield light fromthe HMD when both the HMD and the dark adaptation accessory device areproperly worn. The dark adaptation accessory device may also include anattachment body fixed to the front end of the light shield casing, wherethe attachment body includes various electronic equipment to performbleaching operations. The attachment body may include a set oflight-emitting diodes (LEDs) to emit light at a bleaching intensity. Insome embodiments, the set of LEDs is directed towards the anterior endof the light shield casing. Light emission by the set of LEDs may bevisible through the lenses of an HMD. In addition, the light shieldcasing may include a set of apertures through which cameras ormicrophones of the HMD may continue to collect data.

The attachment body may also include circuitry that is at leastpartially enclosed within the attachment body, where the circuitry mayinclude integrated circuits, microprocessors, microcontrollers, etc. Thecircuitry may include controller circuitry in electrical communicationwith the set of LEDs that is configured to control the light emission ofthe set of LEDs. The circuitry may also include safety circuitry inelectrical communication with the set of LEDs to deactivate the set oflight-emitting diodes independently of the controller circuitry.Independent safety circuitry for the set of LEDs, may reduce thepossibility of user error or program errors exposing a user to adamaging amount of bleaching light.

Various other aspects, features, and advantages of the invention will beapparent through the detailed description of the invention and thedrawings attached hereto. It is also to be understood that both theforegoing general description and the following detailed description areexamples, and not restrictive of the scope of the invention. As used inthe specification and in the claims, the singular forms of “a,” “an,”and “the” include plural referents unless the context clearly dictatesotherwise. In addition, as used in the specification and in the claims,the term “or” means “and/or” unless the context clearly dictatesotherwise. Additionally, as used in the specification, “a portion”refers to a part of, or the entirety of (i.e., the entire portion), agiven item (e.g., data) unless the context clearly dictates otherwise.Furthermore, a “set” may refer to a singular form or a plural form, suchas that a “set of items” may refer to one item or a plurality of items.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part ofthis specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention.

FIG. 1A is a first view of an example head-mounted display (HMD) andaccessory system, in accordance with one or more embodiments.

FIG. 1B is a second view of the example HMD and accessory system, inaccordance with one or more embodiments.

FIG. 2 is a diagram of an attachment body of an attachment device, inaccordance with one or more embodiments.

FIG. 3 depicts an HMD and accessory system being used in conjunctionwith a computer system, in accordance with one or more embodiments.

FIG. 4 is a flowchart of operations to perform dark adaptation testingusing an accessory device, in accordance with one or more embodiments.

FIG. 5 is a flowchart of operations to perform testing with an HMD andaccessory device system, in accordance with one or more embodiments.

FIG. 6 is a block diagram of a computer system as may be used toimplement certain features of some of the embodiments.

DETAILED DESCRIPTION

In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of the embodiments of the invention. It will beappreciated, however, by those having skill in the art, that theembodiments of the invention may be practiced without these specificdetails or with an equivalent arrangement. In other cases, well-knownstructures and devices are shown in block diagram form in order to avoidunnecessarily obscuring the embodiments of the invention.

A head-mounted display (HMD) is a versatile device capable of performingvarious types of virtual reality or augmented reality operations. TheseHMDs permit a user to test a subject's health by exposing the subject tovarious visual or auditory stimuli and collecting readings of thesubject's response to the visual or auditory stimuli in the form ofeye-related readings. Such readings may provide valuable information,such as blood glucose amount, bleaching recovery time, etc. Thisinformation may then be used to diagnose health conditions, such asdiabetes, glaucoma, or age-related macular degeneration.

In many cases, the visual stimuli that an HMD may emit may be limitedwith respect to color or brightness. For example, an HMD may beincapable of emitting bleaching light that would adequately bleach therhodopsin of an eye. Without being capable of providing such bleachinglight, typical systems may produce inaccurate results or require the useof room-scale bleaching equipment. Furthermore, in the case of an HMDthat includes one or more transparent lenses, ambient light or lightfrom other light sources may pollute or otherwise invalidate eye-relatedreadings made by the HMD.

To overcome such challenges or other challenges, some embodiments mayaugment an HMD with an attachment device to shield a subject's eye fromundesirable light and further expose the eye to bleaching light. Itshould be noted that the attachment device may be referred to as anattachment, accessory, or accessory device in some instances, and thatthese terms are non-limiting with respect to any relationship to an HMD.In some embodiments, an attachment device for an HMD may preserve theenvironmental awareness capabilities provided by an HMD by including aseries of apertures that permit HMD sensors to continue acquiring datafrom its environment. For example, the attachment device may include aset of apertures that permit cameras on an HMD to continue collectingvisual data and another set of apertures that permit microphones on theHMD to continue collecting auditory data from the HMD's environment. Inaddition, by including an attachment device to emit bleaching light, theattachment device may include additional safety circuitry that willprotect a subject's eye from over-long bleaching light.

FIG. 1A is a first view of an example head-mounted display (HMD) andaccessory system, in accordance with one or more embodiments. The HMDand accessory system 100 includes an HMD 101, a light shield casing 140,an attachment body 110 that is fixed to the light shield casing 140. TheHMD and accessory system 100 is bisected into a left section and rightsection by the sagittal plane 191 and may be separated into an upper andlower portion by the transverse plane 192. While the attachment body 110is shown as an accessory body to the HMD 101 and may be disconnectedfrom the HMD 101, some embodiments may integrate the attachment body 110with the HMD 101 such that the attachment body 110 may be completelyintegrated with the HMD 101.

The HMD 101 includes a foam member 121, where the foam member 121 may beused to cushion a head as the light shield casing 140 is worn by thehead. The HMD 101 may include a set of cameras usable for capturingvisual information, a set of microphones to capture audio information,an orientation sensor to capture an orientation of the device withrespect to a floor, etc. The set of cameras of the HMD 101 may includeexterior-facing cameras 151-154 to capture visual information of anenvironment surrounding the HMD 101. The set of cameras of the HMD 101may also include interior-facing cameras to capture eye-relatedinformation, such as a position or orientation of an eye. The HMD 101may include additional cameras that are not shown in FIG. 1A or FIG. 1B.In some embodiments, the set of exterior-facing cameras of an HMD may beadjacent to a transparent lens of the HMD. Furthermore, as used in thisdisclosure, cameras may be on opposite sides of the transparent lensesby being symmetric to each other about the sagittal plane 191. Forexample, the exterior-facing camera 151 may be opposite of thetransparent lens with respect to the exterior-facing camera 154.

As shown in FIG. 1B, the light shield casing 140 includes a cavity 124.When a subject's head wears the HMD and accessory system 100, asubject's face may cover the cavity 124 such that light is shielded fromthe cavity 124. In some embodiments, lenses of an HMD may be positionedinside of the cavity 124 such that light from external light sources isblocked from the inside of the cavity 124 and does not penetrate thelenses of the HMD. The light shield casing 140 may shield light from thecavity by forming a seal against light using a lip 160 of the lightshield casing 140, where the lip 160 may be constructed from a flexiblematerial, such as a flexible polymer. As used in this disclosure, alight source may include a direct source of light, such as the sun, alight bulb, a light-emitting diode (LED), etc. A light source may alsoinclude an indirect source of light, such as a mirror or a reflectionoff a surface.

The light shield casing 140 includes a plurality of apertures 141-144and may include additional apertures not shown in FIG. 1A or FIG. 1B.The plurality of apertures 141-144 may be aligned with the light shieldcasing 140 such that the exterior-facing cameras 151-154 of the HMD 101may capture images or other types of information through the apertures141-144. As used in this disclosure, an aperture may be considered to bealigned with a camera when the camera is capable of acquiring images orother visual data through the aperture. Furthermore, an aperture may bealigned with multiple cameras if the aperture is sufficiently large suchthat the multiple cameras may each capture visual information throughthe aperture. For example, the apertures 142-143 may be replaced by asingle aperture such that the exterior-facing cameras 152-153 arealigned with the single aperture. Furthermore, while not displayed, thelight shield casing 140 may include a second microphone aperture that issymmetric to the microphone aperture 182 about the sagittal plane 191.Furthermore, the light shield casing 140 may include a microphoneaperture 182, where a microphone 183 of the HMD 101 may record soundfrom the surrounding environment of the HMD 101. In addition, while thelight shield casing may be described with three apertures, a lightshield casing having other numbers or configurations of apertures ispossible. For example, a light shield casing may include one aperture,two apertures, three apertures, a number of apertures greater than threeapertures, some other number of apertures, etc. For example, theplurality of apertures of a light shield may include at least sixapertures, where at least one of the six apertures may be configured toalign with a microphone or other audio recording device.

When the light shield casing 140 is positioned to encompass an HMD, theholes 141-144 may permit cameras of the HMD to capture surroundingvisual information or other information while still blocking light fromone or more lenses of the HMD. By permitting the cameras, microphones,or other sensors of an HMD to remain functional while the HMD issurrounded by the light shield casing 140, an HMD may be capable ofperforming operations that rely on data from the sensors while stillshielding a wearer's eyes from unwanted light. In some embodiments, theHMD and accessory system 100 may be used as a dark adaptation testingdevice. For example, the HMD 101 may collect visual information via theexterior-facing cameras 151-154 while partially within the light shieldcasing 140 to determine a position of the HMD 101 during a darkadaptation test without influencing the light perceived by a wearer ofthe HMD 101.

The attachment body 110 is fixed to an anterior end (i.e., front end) ofthe light shield casing 140 such that the posterior end (i.e., back end)of the attachment body 110 is facing towards the cavity 124. When thelight shield casing 140 is then fitted over an HMD, an LED of theattachment body 110 may emit light. The light may pass through a lens ofthe HMD and be visible to an eye. In some embodiments, the attachmentbody 110 may be detachable from the light shield casing 140.Alternatively, the attachment body 110 may be permanently fixed to thelight shield casing 140. In some embodiments, the anterior end of thelight shield casing 140 may be formed such that light is shielded fromcavities formed by the light shield casing 140 without requiring thatthe attachment body 110 is attached to the light shield casing 140.

The attachment body 110 includes a midsection 112, where the midsection112 is positioned above a nose protrusion 130 of the light shield casing140. The midsection 112 may be thinner along a vertical axis of theattachment body 110 in comparison to a left section or a right sectionof the attachment body 110. The nose protrusion 130 may include anopening 131 in the bottom direction of the HMD and accessory system 100,where a human nose may fit inside the nose protrusion 130. In someembodiments, the nose protrusion 130 may include a non-rigid member 132,such as a foam member or an elastic member. The non-rigid member 132 mayprevent light from reaching the cavity 124 via the opening 131.

While the attachment body 110 and the light shield casing 140 are shownto be symmetric with respect to the sagittal plane 191, otherembodiments are possible. For example, some embodiments may include aset of apertures on a left section of the light shield casing 140 whilenot having apertures on a right section of the light shield casing 140.Alternatively, some embodiments may include an attachment body that isasymmetric in shape or may be fixed to a light shield casing in anasymmetric manner.

In some embodiments, the attachment body 110 and the light shield casing140 may be physically separate components. Alternatively, in someembodiments, an attachment body and a light shield casing may be part ofa unibody construction or may be otherwise fused together. Furthermore,while the lip 160 may be a flexible polymer in some embodiments, the lip160 may include alternative materials or include additional materials inother embodiments. For example, the lip 160 may be made of or otherwiseinclude a foam cushion, a rigid material, etc.

FIG. 2 is a diagram of an attachment body of an attachment device, inaccordance with one or more embodiments. The posterior end of theattachment body 200 is shown with attachment members 221-226, whereattachment members 221-226 may fix the attachment body to a light shieldcasing at a plurality of attachment positions. As used in thisdisclosure, an attachment member may include any item or combination ofitems used to attach one object with another object at their respectiveattachment positions. An attachment member may include threaded members,such as screws, bolts, nuts, male coupling members, female couplingmembers, etc. Furthermore, some embodiments may use more than one typeof attachment members. For example, the attachment members 221-224 mayinclude screws, and the attachment members 225-226 may include bolts.Various other types of coupling mechanisms or materials may be used. Forexample, the attachment members 221-226 may include snap fastenermembers, adhesive materials, solder, other metals, etc.

The attachment body 200 may include a first LED 231 and a second LED232. The attachment body 200 may also at least partially enclosecontroller circuitry 250, where the controller circuitry 250 is inelectrical communication with the LEDs 231-232. The controller circuitry250 may include an integrated circuit, a microprocessor, amicrocontroller, or other circuitry to control the operations of theLEDs 231-232. The attachment body 200 may also include an interface 252,where the computing devices may send commands to and receive data fromthe controller circuitry 250 via the interface 252. For example, theinterface 252 may include a wireless network antenna such that thecontroller circuitry may receive commands to activate or deactivate theLEDs 231-232 via wireless messages received by the interface 252. Thefirst and second LEDs may be positioned at a posterior end of theattachment body 200, where the posterior end of the attachment body 200may be fixed to an anterior end of a light shield casing.

The first LED 231 and second LED 232 may each be part of a panel of LEDsor another collection of LEDs. For example, the first LED 231 may besurrounded by other LEDs to form a first set of LEDs. The second LED 232may be surrounded by other LEDs to form a second set of LEDs. The firstLED 231 and second LED 232 may be substantially symmetric with respectto a sagittal plane 291 of the attachment body 200. As used in thisdisclosure, a first item may be substantially symmetric to a second itemwith respect to a point, line, or plane if the distance from an edge ofthe first item to the point, line, or plane is within 25% of thedistance from an edge of the second item to the point, line, or plane.In some embodiments, the distance between the first LED 231 and thesecond LED 232 may be determined based on an approximation of thedistance between two retinas. For a human head, the distance between thefirst LED 231 and second LED 232 may be a distance greater than or equalto 40 millimeters (mm), greater than 50 mm, greater than 60 mm, orgreater than some other value. For example, the distance between thefirst LED 231 and second LED 232 may be 45 mm, 50 mm, 55 mm, 60 mm, 62mm, 65 mm, or some other value. Furthermore, the LEDs 231-232 may beconfigured to illuminate an eye to satisfy a size requirement of theilluminated region. For example, an LED may be configured to illuminatea region of the eye such that at least one arc of the illuminated regionhas an arc size that is greater than one degree, a value greater thanone degree, two degrees, a value greater than two degrees, etc.

The first and second LEDs 231-232 are positioned at locations below atransverse plane 292 of the attachment body 200. The position of thefirst and second LEDs 231-232 may be advantageous for certain types ofbleaching operations, such as bleaching operations that target theinferior visual meridian of an eye. While the first and second LEDs231-232 are below the transverse plane 292, other embodiments mayinclude an attachment body having one or more LEDs above a transverseplane of the attachment body. LEDs above the transverse plane of theattachment body may be more suitable for illuminating a superior visualmeridian of an eye.

The attachment body 200 may also include safety circuitry 260, where thesafety circuitry 260 may also be in electrical communication with theLEDs 231-232. In some embodiments, the safety circuitry 260 may besimpler than the controller circuitry 250 with respect to the number ofcircuitry components or the capabilities of the respective circuitrycomponents. The safety circuitry 260 may act independently of thecontroller circuitry 250 and be configured to deactivate the LEDs231-232 under certain conditions. In some embodiments, such conditionsmay be related to the overexposure to bleaching light. As used in thisdisclosure, a bleaching light is a light having a sufficient intensityto bleach the photoreceptors of an eye (“bleaching intensity”) such thatthe vision of the eye is temporarily impaired or eliminated. Forexample, an LED may emit bleaching light by emitting with a light outputthat is greater than or equal to a bleaching threshold, where thebleaching threshold may be a value greater than 1000 lumens, such as1200 lumens, 1300 lumens, 1400 lumens, etc.

The safety circuitry may include a set of relays to deactivate the LEDs231-232 when a set of LEDs have emitted bleaching light for a durationthreshold. Alternatively, or in addition, the safety circuitry mayinclude a microcontroller that is configured to deactivate the set ofLEDs based on a determination that the set of LEDs has emitted bleachinglight for the duration threshold. The duration threshold may vary basedon a test, patient biology, or other factors and may be greater than onesecond, greater than three seconds, greater than five seconds, greaterthan ten seconds, etc. For example, some embodiments may set theduration threshold to be equal to six seconds or some other durationless than ten seconds.

The safety circuitry 260 may inhibit overbleaching in various ways. Insome embodiments, the safety circuitry 260 may be configured such that apower consumption of the LEDs may be used as a threshold to determinewhether a bleaching light is being generated by the set of LEDs. Forexample, the safety circuitry 260 may be configured to deactivate thefirst LED 231 if the power consumption of the LED 231 exceeds athreshold and if the power consumption is maintained for a durationthreshold. Such operations may be useful if the first LED 231 operatesas a variable brightness LED capable of emitting both bleaching andnon-bleaching light, where the brightness of the first LED 231 maydepend on the amount of power provided to the first LED 231.

While the safety circuitry 260 is shown as a single unit that is inelectrical communication with both the first LED 231 and the second LED232, other embodiments may include multiple safety circuitries that areindependent of each other and connected to different sets of LEDs. Forexample, an attachment body may include first safety circuitry that isconnected to a first set of LEDs and a second safety circuitry that isconnected to a second set of LEDs, where controller circuitry may beconnected to and be capable of controlling both the first and secondsets of LEDs.

Alternatively, the safety circuitry 260 may be configured to account foran LED that emits a bleaching light by default. For example, the firstLED 231 may be constructed such that activation of the first LED 231 issufficient to generate a bleaching light. The safety circuitry 260 maybe configured to account for such types of LEDs by deactivating thefirst LED 231 based on a determination that the first LED 231 hascurrent passing through the LED for a duration that is greater than aduration threshold. Furthermore, instead of measuring power directly,the safety circuitry may receive measurements from a brightness sensorthat indicates whether the first LED 231 is emitting a bleaching light.Based on a set of readings provided by a brightness sensor indicatingthat the first LED 231 is emitting a bleaching light for a durationgreater than a duration threshold, some embodiments may deactivate thefirst LED 231.

In some embodiments, one or more LEDs of an attachment body may bemovable along one or more directions. For example, the first LED 231 maybe slidable in a horizontal direction along a set of tracks 241 and maybe slidable in a vertical direction along a set of tracks 242.Similarly, the second LED 232 may be slidable in a horizontal directionalong a set of tracks 243 and may be slidable in a vertical directionalong a set of tracks 244. In some embodiments, a movable LED may bemoved directly, such as by applying force on an LED. Alternatively, someembodiments may include a lever or other mechanism to reconfigure theposition of one or more LEDs of an attachment body.

FIG. 3 depicts an HMD and accessory system being used in conjunctionwith a computer system, in accordance with one or more embodiments. Asubject 395 may wear the HMD 301, which may include a computing device307, where the computing device 307 may include a processor,microprocessor, controller, or other circuitry. In some embodiments, aneye 396 of the subject may be capable of viewing light provided by alight source 399 through lenses 370 of the HMD 301 when the lenses 370is not within an accessory device 302, where the accessory device 302may include a light shield casing 340 and an attachment body 310. TheHMD 301 may include an interior-facing camera to capture eye-relatedinformation and a set of exterior-facing cameras that include anexterior-facing camera 382.

In some embodiments, the accessory device 302 may be placed over the HMD301. The light shield casing 340 may include a cavity 324 that mayencompass a portion of the HMD 301 such that the lenses 370 are withinthe cavity 324. In addition, the light shield casing 340 may include aneutral density filter 334. The neutral density filter 334 may be fixedto the shield casing 340 via a filter coupling 333.

Once the light shield casing 340 is positioned over the HMD 301, lightfrom the light source 399 may be shielded from the lenses 370 by thelight shield casing 340. However, an aperture 342 may permit theexterior-facing camera 382 to continue capturing visual information fromthe surroundings. For example, the exterior-facing camera 382 maycontinue to read light information from the light source 399 via lightpassing from the exterior through the aperture 342.

The attachment body 310 includes an LED 332, where the LED 332 may emita bleaching light, where a bleaching light may be a light with aspectrum and illuminance such that a retina is bleached. For example,the LED 332 may emit a bleaching light having a wavelength of or setwavelengths within the visible spectrum for a human eye (i.e., awavelength between 380 nm to 700 nm). Various types of wavelengthspectrums may be used as bleaching light. For example, a bleaching lightmay include light having a spectrum centered around 550 nm that isgreater than a bleaching threshold. A bleaching threshold may representa threshold luminosity such that light having a luminosity greater thanthe threshold may be considered a bleaching light that is sufficient tobleach photoreceptors. For example, a bleaching light may have aluminosity equal to 1.0×101\4 cd/s.m{circumflex over ( )}2, greater than1.0×10{circumflex over ( )}4 cd/s.m{circumflex over ( )}2, equal to1.0×10{circumflex over ( )}5 cd/s.m{circumflex over ( )}2, greater than1.0×10{circumflex over ( )}5 cd/s.m{circumflex over ( )}2, or some othervalue, such as 1.8×10{circumflex over ( )}4 cd/s.m{circumflex over( )}2.

In some embodiments, a user may initiate an eye-related test using acomputing system 380 that is in communication with the HMD 301 and theattachment device that includes the attachment body 310 and the lightshield casing 340. The computing system 380 may include a standalonecomputer capable of operating without connecting to another computingdevice outside of a local network. Alternatively, or in addition, thecomputing system 380 may include a computing system that receivesprogram instructions or required data from an external data source notavailable through a local network.

In some embodiments, the computing system 380 may initiate operations toperform dark adaptation testing or another eye-related test. Thecomputing system 380 may communicate with the HMD 301 via a wirelessconnection or wired connection. For example, the computing system 380may send a wireless message to the computing device 307 to initiate adark adaptation test or another visual test. Similarly, the computingsystem 380 may communicate with the light shield casing 340 or theattachment body 310 via a wired or wireless connection. For example, thecomputing system 380 may send a command to the attachment body 310 via aBluetooth® connection, where the command may cause the attachment body310 to activate the LED 332.

In some embodiments, the computing system 380 may communicate with boththe HMD 301 and the attachment body 310 to perform one or moreoperations. For example, the HMD 301 may present an initial set ofinstructions to a subject 395 and request a response from the subject395. After the subject 395 provides a requested response (e.g., pressinga button, making a statement, etc.), the computing system 380 may send afirst set of instructions to the HMD 301 to calibrate readings to moreaccurately measure eye-related data associated with the eye 396. Afterthe HMD 301 sends a message to the computing system 380 that calibrationoperations have been completed, the computing system 380 may sendinstructions to the attachment body 310 to emit a bleaching light. Thecomputing system 380 may determine the position of a fixation pointbased on eye-related readings and a known position of the LED 332, andsend a message to the HMD 301 that causes the HMD 301 to display avisual stimulus at the fixation point on the lenses 370. After receivinga message from the HMD 301 that the eye 396 has set its gaze at thefixation point, the computing system 380 may send a message to theattachment body 310 that causes the attachment body 310 to emit ableaching light using the LED 332.

In some embodiments, an application executed by the computing device 307of the HMD 301 may be used to control operations of components of theattachment body 310 or other electronic components. For example, theapplication executed by computing device 307 may begin a visual testprogram and send a wireless message to a circuitry of the attachmentbody 310 to activate the LED 332 by using a wireless headsetcommunication subsystem 303. The wireless message may be based on one ofvarious types of communication standards, such as a Bluetooth standard,a Wi-Fi Direct standard, a near field communication (NFC) standard, aZigBee® standard, a 6LoWPAN standard, etc.

In some embodiments, an application being executed by the computingdevice 307 may retrieve data from the interior-facing camera 383 andsend instructions to control the LED 332 based on this data. Forexample, the computing device 307 may execute an application to performa Viola-Jones object detection framework to detect an eye in a set ofimages using a boosted feature classifier based on video data providedby the interior-facing camera 383. In some embodiments, the applicationmay determine a size associated with the eye and whether this sizesatisfies a minimum threshold. For example, the computing device 307 mayuse a set of classifiers to detect a pupil size based on imagescollected by the interior-facing camera 383 and determine whether thepupil size satisfies a threshold. In response to a determination thatthe pupil size satisfies the threshold, the computing device 307 mayactivate the LED 332 by sending a wireless message via the wirelessheadset communication subsystem 303 to the attachment body 310. Afterreceiving the wireless message from the computing device 307, acircuitry 311 of the attachment body 310 may activate the LED 332 basedon parameters of the wireless message. Furthermore, the applicationexecuted by the computing device 307 may permit additional sensor datato trigger the activation of the LED 332, such as by receiving voiceinstructions captured from a microphone 381, motion detected by theexterior-facing camera 382, feeling a set of touches on the body of theHMD 301, etc.

In some embodiments, the computing device 307 may modify instructions tothe LED 332 based on the detected pupil size. For example, the computingdevice 307 may reduce the intensity of the light emitted by the LED 332in response to detecting greater pupil sizes. For example, the computingdevice 307 may send a first message to the attachment body 310 thatcauses the LED 332 to luminesce with a greater intensity when a pupilsize is less than 4 mm and cause the LED 332 to luminesce with a lesserintensity when the pupil size is greater than 4 mm. Furthermore, someembodiments may determine that a pupil is insufficiently bleached basedon data provided by the interior-facing camera 383 and extend anemission duration of the LED 332. Alternatively, or additionally, theLED 332 may be part of an LED panel, such that a greater number of LEDsmay be activated for smaller pupil sizes. Furthermore, some embodimentsmay use a function that indicates a negative correlation between a pupilsize and an amount of light from the LED 332 or an LED panel comprisingthe LED 332. For example, some embodiments may use a function “L=(K₁-r) * K₂,” where L is a luminosity, “K₁” is a first constant, “r” isa retina size, and “K₂” is a second constant. Some embodiments maydynamically determine an electrical current used to activate the LED 332or a total number of LEDs to activate for a bleaching operation based onthe computed luminosity “L.”

In some embodiments, a testing application executed by the computingdevice 307 may detect that the gaze location of the subject 395 isfocused on a target user interface (UI) element or looking in a targetdirection based on data collected by the interior-facing camera 383. Inresponse, the application may send instructions to the attachment body310 to activate the LED 332. For example, the HMD 301 may display a setof instructions that causes the subject 395 to look at a target UIlocation. In some embodiments, the target UI location may be representedby a target region associated with a target UI location, such that agaze location determined to be within the target region is considered tobe focused at the target UI location. In response to a determinationthat the gaze location of the eye 396 is focused on the target UIlocation based on images provided by the interior-facing camera 383, theapplication may activate the LED 332. Furthermore, the application maysend another message to the attachment body 310 to turn off the LED 332based on a determination that the target UI location is no longer afocus of the user's gaze. Alternatively, some embodiments may foregowaiting for the subject 395 to focus on a particular UI location or aparticular direction before activating the LED 332. Some embodiments maydetermine a gaze location or direction of the eye 396, determine asubset of a set of LEDs that are near the gaze location or direction,and activate this subset of LEDs to bleach or stimulate the eye 396.

Some embodiments may perform calibration operations to determine an LEDintensity, a number of LEDs to activate, an activation duration, oranother LED operational parameter. For example, some embodiments mayobtain feedback from the subject 395 indicating that an LED intensitywas too uncomfortable after an initial testing session. Based on thefeedback, some embodiments may then adjust an amount of current passingthrough the LED 332 for the user during a later testing session byreducing the total current. Some embodiments may further combine thesubject's feedback with other feedback to update a default set ofparameters transmitted by the computing device 307 when activating theLED 332 for other subjects.

The application may then send a second message to the circuitry todeactivate the LED 332 after a pre-determined bleaching durationthreshold is satisfied. Alternatively, or in addition, the applicationmay be triggered by a user command (e.g., a button press, a voicecommand, etc.) or in response to sensor data (e.g., sensor data capturedby the exterior-facing camera 382) to activate or deactivate thebleaching light. Furthermore, sensor data that captures aninterior-facing camera 383 of the computing device 307 may cause thecomputing device 307 to send a message to the circuitry of theattachment body 310. For example, an application executed by thecomputing device 307 may determine that a user's eyes are closed or arenot adequately bleached by based on a set of images captured by theinterior-facing camera 383 and, in response, activate the LED 332 orextend duration of activation of the LED 332.

FIG. 4 is a flowchart of operations to perform dark adaptation testingusing an accessory device, in accordance with one or more embodiments.Some embodiments may obtain a set of readings of an eye, as indicated byblock 404. Various types of eye-related readings may be collected froman eye using one or more sensors. Eye-related readings may includeimages of an eye, colors of an eye, brightness of a section of an eye,or other information that may be captured by a camera or another type ofsensor. Furthermore, such readings may be processed to determine othertypes of eye-related information, such as measurements of a pupil sizeor another size of one or more features of an eye, the color of one ormore features of an eye, the orientation of an eye, etc. For example,some embodiments may collect eye-related readings and process theeye-related readings to determine eye-related information such as theangle of an eye with respect to the focal point of the eye and areference direction, such as a horizontal or vertical direction. Othereye-related readings may include a retina infrared light reflectionmeasurements, other light reflection measurements, motion sensorreadings, etc. As described elsewhere in this disclosure, someembodiments may determine the position of an eye with respect to anilluminating component, such as an LED. Some embodiments may continue tomeasure eye-related data throughout an operation. Furthermore, asdescribed elsewhere in this disclosure, some embodiments may adjust oneor more parameters of the operation in response to the measurements.

In some embodiments, the sensors used to measure eye-related data may beattached to an HMD. For example, the HMD may include a set ofinterior-facing cameras to measure eye responses to stimuli.Alternatively, or in addition, the sensors used to measure eye-relateddata may be attached to a light shield casing or attachment body. Forexample, a light shield casing that encloses a portion of an HMD mayinclude an infrared camera or another type of sensor to measureeye-related information.

Some embodiments may present a visual stimulus to fix a gaze, asindicated by block 412. Some embodiments may present a visual stimulusover the course of an examination operation. For example, someembodiments may present a circular shape that is one degree in diameterat a determined fixation position.

Some embodiments may determine the position of a visual stimulusdesigned for fixation based on the eye-related readings described forblock 404. For example, some embodiments may use the eye-relatedreadings to determine a fixation position that would cause an eyefixated at the fixation position to be a preset number of degrees froman LED or within a preset range from the LED. The preset number ofdegrees or preset range may vary based on a specific application or typeof operation. For example, some embodiments may determine a fixationposition such that the visual stimulus location is six degrees above ableaching location. In such a configuration, a bleaching LED may providea bleaching light that is centered at six degrees on the inferior visualmeridian of an eye. Some embodiments may then display a visual stimulusat the fixation position on the lens of an HMD or may otherwise presentthe visual stimulus on a surface that may be viewed through the lens ofthe HMD.

Some embodiments may generate a warning if a sensor detects that the eyehas gone beyond a threshold with respect to the angular distance betweenits fixated gaze and a fixation point. For example, some embodiments maydetermine that an eye has shifted its focus away from a fixation pointby more than 30% based on sensor measurements acquired from sensors ofan HMD and, in response, present a warning using the HMD.

Some embodiments may adjust a stimulus brightness based on measurementswhile the stimulus is being presented. For example, some embodiments maycontinuously measure a pupil radius. Some embodiments may then determinea new stimulus brightness by multiplying a preset brightness of thestimulus by a factor that is inversely proportional to a pupil radius ora function that is positively correlated with the pupil radius. Forexample, some embodiments may determine a brightness for a stimulus bymultiplying a preset brightness by the value 2/x{circumflex over ( )}2,where “x” may be the value of a pupil radius in millimeters.

Some embodiments may present a bleaching light, as indicated by block428. As described elsewhere in this disclosure, some embodiments maysend a message to a device containing bleaching light, such as anattachment body that includes an LED capable of emitting a bleachinglight. The attachment body may include controller circuitry that maycause the LED to emit the bleaching light and may further determinewhich subset of LEDs of a set of LEDs to activate. An LED may be causedto emit a bleaching light that is at least four degrees in diameter onthe surface of a retina.

Some embodiments may combine the brightness of an HMD with the lightemitted from an LED of an attachment body to generate a bleaching light.For example, some embodiments may display a first light on a lens usingan HMD. Some embodiments may then activate an LED of an attachment body,where the light from the LED and the HMD may combine to form a bleachinglight. For example, some embodiments may determine that an eye isfixated at a first position and further determine that an LED of anattachment body would illuminate at six degrees below a horizontal angleof an eye. In response, some embodiments may display a light using theHMD that is also six degrees below the horizontal angle of the eye suchthat the light from the LED and the light displayed by the HMD arealigned with respect to the center of an eye.

In some embodiments, the device used to provide bleaching light mayinclude a plurality of LEDs capable of emitting bleaching light. Someembodiments may then determine which of the plurality of LEDs toactivate to most effectively bleach a retina. For example, someembodiments may determine that a fixation position is at a specifiedlocation and, in response, select an LED that is at least six degreesbelow the fixation position. After activation, the selected LED may thenemit bleaching light.

Some embodiments may determine whether a bleaching light durationsatisfies a set of deactivation criteria, as indicated by block 432. Insome embodiments, an attachment body used to emit bleaching light mayinclude safety circuitry to prevent the dangerous durations of bleachinglight. The safety circuitry or a computing device may include a set ofdeactivation criteria to prevent the emission of an unsafe amount ofbleaching light by stopping the device from emitting the bleachinglight. In some embodiments, satisfying a set of deactivation criteriamay include satisfying a threshold, where the threshold may be aduration threshold, a power consumption threshold, etc. In many cases, ableaching light may be deactivated if the device emits a bleaching lightfor longer than a duration threshold.

Some embodiments may use safety circuitry that is in electroniccommunication with the LED but operates independently of controllercircuitry or other circuitry used to control the LED. The safetycircuitry may include various types of electronic components such asrelays or microcontrollers, where the electronic components may beconfigured to deactivate an LED. The electronic components of safetycircuitry may be configured to determine that a bleaching light durationhas exceeded a duration threshold in response to a determination that anLED has been provided at least a preset amount of power for at least theduration threshold. For example, some embodiments may use amicrocontroller of the safety circuitry to determine whether a set ofLEDs has consumed enough power to exceed a power threshold. The powerthreshold may be a value such as 0.001 Watts (W), a value greater than0.001 W, 0.1 W, a value greater than 0.1 W, or some other value. Inresponse to a determination that the set of LEDs has a power consumptionthat satisfies a power threshold (e.g., by being greater than the powerthreshold, by being greater than or equal to the power threshold, etc.),some embodiments may then determine the light emission duration of theset of LEDs satisfies a duration threshold (e.g., by being greater thanthe duration threshold, by being greater than or equal to the durationthreshold, etc.). In some embodiments, the duration threshold may be0.01 seconds, a value less than 0.01 seconds, one second, a value lessthan one second, five seconds, a value less than five seconds, sixseconds, a value less than six seconds, ten seconds, a value less thanten seconds, etc.

In some embodiments, operations to determine whether a set of LEDsshould be deactivated may be performed by other circuitry or a computerdevice that is separate from an attachment body. For example, anattachment device may include safety circuitry that deactivates an LEDif the LED is used for longer than six seconds. A controller circuitryof the attachment device may retrieve instructions from a computersystem that causes the controller circuitry to deactivate the LED if theLED is used for longer than one second.

In some embodiments, operations to determine whether a set of LEDsshould be deactivated may include obtaining data from sensors of an HMDor another device that is physically separate from an attachment device.For example, an HMD may provide a retina size or a measured rhodopsincontent to a computer system, where the computer system may thendetermine whether measurements provided by the HMD satisfy a set ofdeactivation criteria. If the computer system determines that themeasurements provided by the HMD satisfy the set of deactivationcriteria, the computer system may then send instructions to thecircuitry of an attachment device to deactivate an LED of the attachmentdevice. In response to a determination that the set of deactivationcriteria has been satisfied, operations of the process 400 may proceedto block 436. Otherwise, operations of the process 400 may proceed toblock 450.

Some embodiments may deactivate a device emitting a bleaching light, asindicated by block 436. As described elsewhere in this disclosure, anattachment device may include controller circuitry to control theactivation or deactivation of an LED and may also include safetycircuitry to deactivate the LED independently of commands sent by thecontrol circuitry. Furthermore, some embodiments may send, to acomputing device, an error message or other indication that the safetycircuitry was activated to deactivate one or more LEDs. In addition,some embodiments may identify the stage of a multistage operation thatrequires multiple iterations of reaching light emission.

Some embodiments may perform post-bleaching testing operations, asindicated by block 450. As described elsewhere in this disclosure, ableaching operation may be used as part of a dark adaptation test. Afterbleaching an eye, some embodiments may display a visual stimulus (e.g.,a flashing light) and wait for a subject's response indicating that thesubject's photoreceptors had sufficiently recovered to perceive thevisual stimulus. Alternatively, some embodiments display a flashing andbleaching light concurrently. For example, some embodiments mayconcurrently display a flashing light on an HMD lens while also using anLED to emit bleaching light. After receiving the subject's response,some embodiments may record the duration between when an LED wasprevented from displaying bleaching light and when the subjectresponded. Some embodiments may then determine whether the durationsatisfies a recovery threshold, where a determination that the subject'srequired time to respond is greater than a recovery threshold mayindicate an eye-related status or a health condition.

FIG. 5 is a flowchart of operations to perform testing with an HMD andaccessory device system, in accordance with one or more embodiments.Some embodiments may execute an application on an HMD, as indicated byblock 504. The HMD may include a set of processors and the memorystoring program code, where the set of processors may execute theprogram code to execute an application on the HMD. In some embodiments,the HMD may obtain the program code used to execute the application or aportion of the program code through an online platform. For example, auser may access an online platform and select an application to causethe HMD to download program code for the application via the onlineplatform.

In some embodiments, operations performed by an HMD may be performed bymultiple applications corresponding with different sets of program code.For example, as described elsewhere in this disclosure, some embodimentsmay capture images with a set of cameras using a first application andprocess the images with a second application to determine pupil sizes orother eye-related information. While some embodiments may be describedas performing operations with a single application, it should beunderstood that any operation, combination of operations, orsub-operations of an operation may be performed by multipleapplications. Furthermore, one or more operations that are described asbeing performed by an HMD may be performed by other computing devices,such as another mobile computing device in the proximity of the HMD, aremote computing device, etc.

In some embodiments, the HMD may be triggered by one or more stimuli toperform other operations described in this disclosure, such as thepresentation of visual stimulus or the transmission of a message thatcauses bleaching light emission. For example, some embodiments mayconfigure the HMD with an application that causes the HMD to perform oneor more operations described in this disclosure based on visual stimuluscaptured by a set of exterior-facing sensors of the HMD. The visualstimulus may include images, brightness measurements, infraredmeasurements, etc. For example, an application executing on the HMD mayperform operations to generate a set of values representing a targetmotion or a target shape based on a shape, motion types, or otherinformation. Such information may be determined based on a set of imagescollected by an exterior-facing camera of the HMD. Some embodiments maythen determine whether the target motion, target shape, or otherinformation satisfies a set of visual stimulus criteria. In response toa determination that the set of visual stimulus criteria is satisfied,some embodiments may initiate a testing operation that causes the HMD toperform one or more operations described in this disclosure, such asoperations to collect eye-related readings as described by block 508,operations to determine eye-related information as described by block512, operations to determine whether a set of light-activating criteriais satisfied as described by block 532, etc.

Various types of applications, modules, services, etc. may be used todetermine the presence of a specific shape, detect a type of motion, orperform other operations based on object recognition. For example, someembodiments may collect image data from an exterior-facing camera andprovide the image data to a machine learning application that detectsthat a hand is present and may further determine a shape or orientationof the hand. After determining that the detected hand is controlled topresent a specific hand signal, the application may cause the HMD toperform one or more operations described in this disclosure. Forexample, some embodiments may send a message to an accessory that causesthe accessory to emit a bleaching light in response to detecting thehand signal. Alternatively, or additionally, some embodiments maycapture images from exterior-facing cameras of the HMD and determine abrightness value based on the set of images. In response to adetermination that the brightness value is below a brightness threshold,some embodiments may initiate a testing operation that includes one ormore operations described by blocks 508, 512, 532, etc.

In some embodiments, the HMD may be configured to wait for an audiostimulus and initiate a testing operation in response to receiving theaudio stimulus. The audio stimulus may be received with a microphone ofthe HMD, and may require that the stimulus be received as a specifictype of sound or sequence of sounds. Alternatively, or in addition, someembodiments may treat the audio stimulus as a voice-activated stimulusand determine whether the audio stimulus satisfies one or morevoice-related criteria. For example, some embodiments may determinewhether a natural language processing application outputs a specificword or a specific set of words when provided with the audio stimulus,whether the audio stimulus is provided by a specific user's voice, etc.After receiving the audio stimulus and determining that the audiostimulus satisfies one or more associated audio stimulus criteria, someembodiments may initiate one or more operations described in thisdisclosure, such as an operation described by block 508, block 512,block 532, etc.

Some embodiments may collect eye-related readings with a set of camerasor other sensors of the HMD, as indicated by block 508. Eye-relatedreadings may include images, such as images collected by a camera. Forexample, some embodiments may collect eye-related readings within a setof interior-facing cameras. In some embodiments, the HMD may collectother types of eye-related readings, such as reflectometry measurements,ellipsometry measurements, etc. When collecting readings, someembodiments may collect readings in a sequence, such as collecting avideo of an eye over a duration.

In some embodiments, the HMD may present visual stimuli to an eye, wherethe visual stimuli may cause the eye to change its gaze to focus on thevisual stimulus. Some embodiments may collect eye-related readingsduring the presentation of a sequence of visual stimuli. For example,some embodiments may present a sequence of dots on a lens of the HMDover a 30-second duration and collect images of the eye with aninterior-facing camera during this 30-second duration. Some embodimentsmay obtain a respective set of images of an eye when each respectivestimulus of the sequence of visual stimuli is displayed on the HMD lens.Some embodiments may then use this information to derive a gaze locationof the eye and other types of eye-related information, as describedelsewhere in this disclosure. For example, some embodiments maydetermine a respective gaze location for each respective stimulus thatis presented on the HMD lens. Some embodiments may activate a bleachinglight in response to a determination that a gaze location is focused ona target region. For example, some embodiments may set the respectivetarget region for a respective stimulus to be within a threshold rangeof a presentation location of a respective stimulus, where the thresholdrange may represent a linear distance, an angular distance, etc.

Some embodiments may determine a pupil size or other additionaleye-related information based on the set of eye-related readings, asindicated by block 512. Some embodiments may use eye-related readings todetermine additional eye-related information. The additional eye-relatedinformation may include information such as whether an eye is open orclosed, a percentage representing the degree to which an eye is open, apupil size, an eye color, an eye orientation, other descriptors of theeye, a health condition related to the eye, a health condition of theperson having the eye, etc.

Some embodiments may determine eye-related information by using a set ofclassifiers of an application executed by an HMD. For example, someembodiments may perform operations to detect image regions indicatingthe presence of eyes by providing an image to a set of classifiers. Someembodiments may then use a second set of classifiers or another set ofimplemented algorithms to determine a pupil size based on the pixels ofthe image regions. For example, some embodiments may perform edgedetection method operations to first draw a set of boundaries for animage of an eye and components of the eye within an image region. Someembodiments may then determine a pupil size based on the set of drawnboundaries. As described elsewhere in this disclosure, some embodimentsmay then determine whether the pupil size satisfies a threshold and, inresponse to a determination that the pupil size satisfies a threshold,send a message to an attachment device using a transmitter of the HMD.

Some embodiments may determine whether a set of light-activatingcriteria is satisfied based on the pupil size or additional eye-relatedinformation, as indicated by block 532. Some embodiments may wait untilthe set of light-activating criteria is satisfied before sending a setof messages to an attachment device that causes the attachment device toemit a bleaching light. Alternatively, or additionally, the set oflight-activating criteria may be divided into subsets of criteria, suchthat the satisfaction of different subsets may cause the transmission ofdifferent sets of messages. For example, some embodiments may send afirst set of messages to the attachment device based on a determinationthat a first subset of criteria is satisfied and send a second set ofmessages to the attachment device based on a determination that a secondsubset of criteria is satisfied.

In some embodiments, the set of light-activating criteria may include acriterion that a pupil size is greater than a minimum threshold, where aminimum threshold may include values less than or equal to 10 mm, valuesless than or equal to 5 mm, values less than or equal to 3 mm, valuesless than or equal to 1 mm, etc. For example, the minimum threshold maybe equal to 5 mm, where some embodiments may determine that the set oflight-activating criteria is satisfied if a determined pupil size isgreater than 5 mm. Alternatively, the minimum threshold may be equal to4 mm, where some embodiments may determine that the set oflight-activating criteria is satisfied if the determined pupil size isgreater than 4 mm.

In some embodiments, the set of light-activating criteria may includemultiple criterion that must each be satisfied in order for a set oflight-activating messages to be transmitted by an HMD. For example, someembodiments may use a set of criteria that include a first criterionthat a pupil size be greater than 4 mm and a second criterion that agaze location for the eye be focused on a specific display location ofthe HMD. Some embodiments may then transmit a set of light-activatingmessages based on a determination that both the first criterion and thesecond criterion are satisfied. Though the above example discloses a setof light-activating criteria having two criteria, other number ofcriteria are possible for inclusion in the set of light-activatingcriteria.

If the set of light-activating criteria is satisfied by the pupil sizeor other eye-related information, operations of the process 500 mayproceed to operations described by block 540. Otherwise, operations ofthe process 500 may return to operations described by block 504.

Some embodiments may transmit a set of messages to an attachment, asindicated by block 540. Some embodiments may wirelessly transmit a setof messages via a communication protocol such as Bluetooth, 2.4 GHzWi-Fi, 5.0 GHz Wi-Fi, or some other wireless communication protocol. Insome embodiments, the set of wireless messages may be the same as otherset of wireless messages transmitted from the HMD to an attachmentdevice. For example, in response to a determination that a thresholdamount of an eye is open at a first time point, some embodiments maysend a first set of messages that causes the attachment device to emit ableaching light. Some embodiments may then send the same set of messagesto the attachment device in response to a determination that thethreshold amount is satisfied at a second timepoint.

Alternatively, some embodiments may send different sets of messagesbased on which subset of criteria is satisfied by eye-relatedinformation. For example, some embodiments may determine a first pupilsize based on a first set of eye-related readings and determine that thefirst pupil size is less than a size threshold. Based on a determinationthat the first pupil size is less than the first threshold, someembodiments may generate or update a first set of messages to include afirst value for a parameter field. Some embodiments may then send thefirst set of messages to an attachment device, where the first value forthe parameter field may cause the attachment device to emit a firstbleaching light at a first intensity for a first duration. Someembodiments may then determine a second pupil size based on a second setof eye-related readings and determine that the second pupil size isgreater than the size threshold. Based on a determination that the pupilsize is greater than the size threshold, some embodiments may generateor update a second set of messages to include a second value that causesthe attachment device to emit a second bleaching light having a lesserintensity than the first bleaching light. Some embodiments may modifythe duration instead of the intensity of a bleaching light based onmessages sent by the HMD. Alternatively, some embodiments may modifyboth a duration and intensity of a light emitted by the attachmentdevice based on a set of messages sent from the HMD.

Some embodiments may determine a parameter value used to control LEDoperations based on a set of user-provided values. For example, someembodiments may receive a user-provided value indicating that ableaching time was too uncomfortable, where the user-provided value maybe provided via the user interacting with a physical button, interactingwith a display on the HMD, providing a verbal input, etc. In response toreceiving the user-provided value, some embodiments may update aconfiguration parameter and then generate a new message based on theconfiguration parameter to include a parameter value that controls aduration or intensity of light emission by a set of LEDs. For example, auser may press a button that updates a configuration parameter used todetermine a light emission intensity. In response to receiving theuser-provided value, some embodiments may reduce a value for theconfiguration parameter by 1, such as by reducing the value for theconfiguration parameter from “1.00” to “0.90,” where the valuerepresents a normalized intensity. Some embodiments may then generate anew message that includes the configuration parameter “0.90,” where thevalue of the configuration parameter may cause an attachment device toemit light with a set of LEDs with an intensity equal to 90% of themaximum intensity of the set of LEDs.

Some embodiments may determine which parameter values to use for a setof messages used to activate a set of LEDs based on a selection of atest category, where the test category may represent different types oftest configurations. For example, some embodiments may receive a firstuser-selected input indicating the selection of a first dark adaptationtesting operation. Some embodiments may then send a first set ofmessages to an attachment, with the first set of messages includesparameters that causes the attachment to activate a first LED subset ofLEDs. Some embodiments may then receive a second user-selected inputindicating the selection of a second dark adaptation testing operation.Some embodiments may then send a second set of messages to theattachment, where the second set of messages includes parameters thatcauses the attachment to activate a second LED subset of LEDs that aredifferent from the first set of LEDs. In some embodiments, the first andsecond LED subsets may emit light at different wavelengths. For example,the first LED subset may emit light at wavelengths centered around 480nanometers (nm) and the second LED subset may emit light at frequenciescentered around 520 nm. By causing the selection of different subsets ofLEDs to be activated, some embodiments may perform specific types ofbleaching that do not require total bleaching of the photoreceptors ofan eye.

Some embodiments may activate a set of LEDs of the attachment inresponse to receiving the set of messages, as indicated by block 544. Asdescribed elsewhere in this disclosure, the set of LEDs may be a part ofan accessory or attachment to an HMD, where a circuitry of the accessoryor other attachment to an HMD may control the set of LEDs. In someembodiments, circuitry of an attachment may receive the set of messagessent by the HMD via a wireless receiver of the circuitry, where thecircuitry stores program instructions to control a set of LEDs based onthe received set of messages. Once activated, the set of LEDs may emitlight at various intensities including a bleaching intensity, where theemitted light may pass through a transparent lens of the HMD.

Some embodiments may receive different parameter values when receivingdifferent sets of messages to activate one or more LEDs. For example, acircuitry of an attachment may configure an intensity of the lightemitted by a set of LEDs based on a parameter value communicated via areceived message sent from an HMD. Alternatively, or additionally, thecircuitry may configure a duration for the light being emitted. Asdescribed elsewhere, the parameter value may be determined by an HMDbased on various types of values, such as eye-related readings, otherassociated eye-related information, user-provided values, etc.

As described elsewhere, an attachment may include a first and secondcircuitry, where a first circuitry may control a set of LEDs based onreceived messages, and where the second circuitry may deactivate the setof LEDs if a set of safety criteria is satisfied. In some embodiments,the second circuitry may deactivate the set of LEDs and send a warningmessage to the HMD indicating that the second circuitry has deactivatedthe set of LEDs if the set of LEDs were configured by a message to emitlight for longer than a duration threshold of the second circuitry. Insome embodiments, the warning message may indicate that the configuredduration exceeds the duration threshold, where the application executingon the HMD may search through a set of configuration parameters used toset or otherwise update LED emission durations. The HMD may then selecta subset of the set of configuration parameters used to control LEDemission durations, where the selected subset exceeds a durationthreshold of the second circuitry. Some embodiments may then visuallyindicate this subset of configuration parameters for a user to update ordelete. Alternatively, some embodiments may automatically update thevalues of this subset of configuration parameters such that none of theupdated configuration parameters will cause the set of LEDs to exceedthe safety duration threshold.

As described elsewhere, some embodiments may collect eye-relatedreadings when the set of LEDs are emitting light. For example, a set ofinterior-facing cameras of the HMD may collect eye-related readings witha camera during a data collection period, where the set of LEDs may emitbleaching light concurrently with the data collection period. The HMDmay determine a set of eye-related information based on the collectedreadings during the first data collection period and determine whetherthe eye-related information satisfies a set of criteria.

Some embodiments may use readings collected during and after a firstdata collection period to determine whether to activate a set of LEDs,collect eye-related readings, or perform other operations for a seconddata collection period. For example, after collecting eye-relatedreadings, some embodiments may collect images of an eye during a firstdata collection period and determine an associated set of eye-relatedinformation indicating an eye pigment recovery rate after an eye isexposed to bleaching light. Some embodiments may then determine whetherthe recovery rate satisfies a recovery rate threshold, where therecovery rate threshold may be a type of time-based criterion. The setof time-based criteria may include various types of criteria, such as acriterion that a rate is greater than or equal to a minimum rate, a rateis less than or equal to a maximum rate, that a total change in a set ofmeasurements or derived value based on the set of measurements satisfiesa change threshold, etc. For example, satisfying the set of time-basedcriteria may include determining a rate of rhodopsin regeneration, rateof cone pigment regeneration, or rate of melanopsin regeneration basedon sensor readings collected by the HMD and determining whether the rateis greater than a minimum rate. Alternatively, or additionally, the ratemay include a rate of change in a pupil size or other adjustmentmechanisms of an eye. In response to a determination that the set oftime-based criteria is not satisfied, some embodiments may then initiatea second testing operation to emit light with the set of LEDs of anattachment and collect a second set of eye-related readings during asecond data collection period. In some embodiments, the HMD maydetermine whether the set of time-based criteria is satisfied based onthe second set of eye-related readings. In response to a determinationthat the second set of eye-related readings satisfies the set oftime-based criteria, some embodiments may store the readings andinformation derived from the readings in a persistent memory of the HMDor another computer device.

It should be noted that the features and limitations described in anyone embodiment may be applied to any other embodiment herein, and aflowchart or examples relating to one embodiment may be combined withany other embodiment in a suitable manner, done in different orders, ordone in parallel. In addition, the systems and methods described hereinmay be performed in real time. It should also be noted that the systemsand/or methods described above may be applied to, or used in accordancewith, other systems and/or methods.

FIG. 6 is a block diagram of a computer system as may be used toimplement certain features of some of the embodiments. The computersystem 600 may include a set of central processing units (“set ofprocessors”) 605, memory 610, input/output devices 625, e.g., keyboardand pointing devices, touch devices, display devices, storage devices620, e.g., disk drives, and network adapters 630, e.g., networkinterfaces, that are connected to an interconnect 615. The interconnect615 is illustrated as an abstraction that represents any one or moreseparate physical buses, point-to-point connections, or both connectedby appropriate bridges, adapters, or controllers. The interconnect 615,therefore, may include, for example, a system bus, a PeripheralComponent Interconnect (PCI) bus or PCI-Express bus, a HyperTransport orindustry standard architecture (ISA) bus, a small computer systeminterface (SCSI) bus, a universal serial bus (USB), an IIC (12C) bus, oran Institute of Electrical and Electronics Engineers (IEEE) standard1394 bus, also called FireWire.

The memory 610 and storage devices 620 are computer-readable storagemedia that may store program instructions that implement at leastportions of the various embodiments. In addition, the data structuresand message structures may be stored or transmitted via a datatransmission medium, e.g., a signal on a communications link. Variouscommunications links may be used, e.g., the Internet, a local areanetwork, a wide area network, or a point-to-point dial-up connection.Thus, computer-readable media can include computer-readable storagemedia, e.g., non-transitory media, and computer-readable transmissionmedia.

In some embodiments, software or firmware may be initially provided tothe computer system 600 by downloading it from a remote system throughthe computer system 600, e.g., via network adapter 630. The providedsoftware or firmware may be stored in memory 610. The programinstructions stored in memory 610 can be implemented as software and/orfirmware to program the set of processors 605 to carry out actionsdescribed above. For example, some embodiments may use the set ofprocessors 605 to determine a set of decision parameters using a neuralnetwork model or another type of machine learning model.

The various embodiments introduced herein can be implemented by, forexample, programmable circuitry, e.g., one or more microprocessors,programmed with software and/or firmware, or entirely in special purposehardwired (non-programmable) circuitry, or in a combination of suchforms. Special-purpose hardwired circuitry may be in the form of, forexample, one or more ASICs, PLDs, FPGAs, etc.

With respect to the components of computer devices described in thisdisclosure, each of these devices may receive content and data viainput/output (hereinafter “I/O”) paths. Each of these devices may alsoinclude processors and/or control circuitry to send and receivecommands, requests, and other suitable data using the I/O paths. Thecontrol circuitry may comprise any suitable processing, storage, and/orinput/output circuitry. Further, some or all of the computer devicesdescribed in this disclosure may include a user input interface and/oruser output interface (e.g., a display) for use in receiving anddisplaying data. In some embodiments, a display such as a touchscreenmay also act as a user input interface. It should be noted that in someembodiments, one or more devices described in this disclosure may haveneither user input interfaces nor displays and may instead receive anddisplay content using another device (e.g., a dedicated display devicesuch as a computer screen and/or a dedicated input device such as aremote control, mouse, voice input, etc.). Additionally, one or more ofthe devices described in this disclosure may run an application (oranother suitable program) that performs one or more operations describedin this disclosure.

Although the present invention has been described in detail for thepurpose of illustration based on what is currently considered to be themost practical and preferred embodiments, it is to be understood thatsuch detail is solely for that purpose and that the invention is notlimited to the disclosed embodiments, but, on the contrary, is intendedto cover modifications and equivalent arrangements that are within thescope of the appended claims. For example, it is to be understood thatthe present invention contemplates that, to the extent possible, one ormore features of any embodiment may be combined with one or morefeatures of any other embodiment.

As used throughout this application, the word “may” is used in apermissive sense (i.e., meaning having the potential to), rather thanthe mandatory sense (i.e., meaning must). The words “include,”“including,” “includes,” and the like mean including, but not limitedto. As used throughout this application, the singular forms “a,” “an,”and “the” include plural referents unless the context clearly indicatesotherwise. Thus, for example, reference to “an element” or “an element”includes a combination of two or more elements, notwithstanding use ofother terms and phrases for one or more elements, such as “one or more.”The term “or” is non-exclusive (i.e., encompassing both “and” and “or”),unless the context clearly indicates otherwise. Terms describingconditional relationships (e.g., “in response to X, Y,” “upon X, Y,” “ifX, Y,” “when X, Y,” and the like) encompass causal relationships inwhich the antecedent is a necessary causal condition, the antecedent isa sufficient causal condition, or the antecedent is a contributorycausal condition of the consequent (e.g., “state X occurs upon conditionY obtaining” is generic to “X occurs solely upon Y” and “X occurs upon Yand Z”). Such conditional relationships are not limited to consequencesthat instantly follow the antecedent obtaining, as some consequences maybe delayed, and in conditional statements, antecedents are connected totheir consequents (e.g., the antecedent is relevant to the likelihood ofthe consequent occurring). Statements in which a plurality of attributesor functions are mapped to a plurality of objects (e.g., one or moreprocessors performing steps/operations A, B, C, and D) encompass bothall such attributes or functions being mapped to all such objects andsubsets of the attributes or functions being mapped to subsets of theobjects (e.g., both all processors each performing steps/operations A-D,and a case in which processor 1 performs step/operation A, processor 2performs step/operation B and part of step/operation C, and processor 3performs part of step/operation C and step/operation D), unlessotherwise indicated. Further, unless otherwise indicated, statementsthat one value or action is “based on” another condition or valueencompass both instances in which the condition or value is the solefactor and instances in which the condition or value is one factor amonga plurality of factors.

Unless the context clearly indicates otherwise, statements that “each”instance of some collection have some property should not be read toexclude cases where some otherwise identical or similar members of alarger collection do not have the property (i.e., each does notnecessarily mean each and every). Limitations as to sequence of recitedsteps should not be read into the claims unless explicitly specified(e.g., with explicit language like “after performing X, performing Y”),in contrast to statements that might be improperly argued to implysequence limitations (e.g., “performing X on items, performing Y on theX′ ed items”) used for purposes of making claims more readable ratherthan specifying sequence. Statements referring to “at least Z of A, B,and C” and the like (e.g., “at least Z of A, B, or C”) refer to at leastZ of the listed categories (A, B, and C) and do not require at least Zunits in each category. Unless the context clearly indicates otherwise,it is appreciated that throughout this specification discussionsutilizing terms such as “processing,” “computing,” “calculating,”“determining,” or the like refer to actions or processes of a specificapparatus, such as a special purpose computer or a similar specialpurpose electronic processing/computing device. Furthermore, unlessindicated otherwise, updating an item may include generating the item ormodifying an existing time. Thus, updating a record may includegenerating a record or modifying the value of an already-generatedvalue.

ENUMERATED EMBODIMENTS

The present techniques will be better understood with reference to thefollowing enumerated embodiments:

-   -   A.1. A system comprising: a head-mounted display comprising        transparent lenses and exterior-facing cameras on a front end of        the head-mounted display and adjacent to the transparent lenses,        wherein at least one pair of cameras of the exterior-facing        cameras are on opposite sides of a vertical plane of the        head-mounted display; and an accessory device positioned on a        front end of the head-mounted display, the accessory device        comprising: a light shield casing comprising: a cavity that        encompasses the transparent lenses of the head-mounted display        when the accessory device is attached to the head-mounted        display, wherein the light shield casing shields the cavity from        light from an environment of the head-mounted display when the        accessory device is attached to the head-mounted display; and a        plurality of apertures aligned with the exterior-facing cameras;        and an attachment body fixed to a front end of the light shield        casing, the attachment body comprising: a set of light-emitting        diodes (LEDs) to emit light at a bleaching intensity, wherein        the set of LEDs is attached to a back end of the attachment body        and is directed towards at least one lens of the transparent        lens, and wherein light emitted by the set of LEDs is visible        through at least one lens of the transparent lenses; and a        circuitry that is at least partially enclosed within the        attachment body and is in electrical communication with the set        of LEDs, wherein the circuitry is configured to control the        light emission of the set of LEDs.    -   A.2. The system of embodiment A.3, wherein the circuitry is a        controller circuitry, and wherein the attachment body further        comprises a safety circuitry that is in electrical communication        with the set of LEDs, wherein the safety circuitry comprises a        relay or microcontroller to deactivate the set of light-emitting        diodes independently of the controller circuitry.    -   A.3. The system of any of embodiments A.1 to A.2, wherein the        controller circuitry is configured to perform operations        comprising: emitting a first light at a first intensity with the        set of LEDs in response to receiving a first command via an        interface of the circuitry, wherein the first intensity is not a        bleaching intensity; and emitting a second light at a second        intensity with the set of LEDs in response to receiving a second        command via the interface, wherein the second intensity is a        bleaching intensity.    -   A.4. The system of any of embodiments A.1 to A.3, wherein the        circuitry performs operations comprising emitting a first light        at a first intensity with the set of LEDs in response to        receiving a first command via an interface of the circuitry,        wherein the first light is emitted concurrently with a light        emitted by the head-mounted display.    -   A.5. The system of any of embodiments A.1 to A.4, further        comprising: a filter coupling; and a neutral density filter        fixed to the filter coupling, wherein the set of LEDs is        directed towards the neutral density filter such that the light        emitted by the set of LEDs passes through the neutral density        filter.    -   A.6. The system of any of embodiments A.1 to A.5, wherein the        plurality of apertures comprises at least six apertures, and        wherein at least one aperture of the plurality of apertures is        aligned with a microphone.    -   A.7. A device comprising: a casing comprising a cavity, wherein        a lens of a head-mounted display is positioned inside the cavity        when the device is attached to the head-mounted display, and        wherein an aperture of the casing is aligned with an        exterior-facing camera of the head-mounted display; and an        attachment body, wherein a posterior end of the attachment body        is fixed to an anterior end of the casing, the attachment body        comprising: a set of light-emitting diodes (LEDs), wherein the        set of LEDs is attached to the posterior end of the attachment        body and is directed towards the lens; and a circuitry that is        configured to control light emission of the set of LEDs.    -   A.8. The device of embodiment A.7, wherein: the lens is a first        lens; the attachment body comprises a midsection that is        bisected by a sagittal plane of the attachment body; the        midsection is longer along the sagittal plane of the attachment        body in comparison to a left section of the attachment body or a        right section of the attachment body; the set of LEDs is a first        set of LEDs; a second set of LEDs is attached to the posterior        end of the attachment body and is directed towards a second lens        of the head-mounted display; the first set of LEDs and the        second set of LEDs are substantially symmetric about the        sagittal plane; and a distance between the first set of LEDs and        the second set of LEDs is greater than or equal to 40        millimeters.    -   A.9. The device of any of embodiments A.7 to A.8, wherein the        circuitry is a first circuitry, and wherein a second circuitry        comprises a microcontroller configured to perform operations        comprising: determining whether a power consumption of the set        of LEDs satisfies a power threshold; in response to a        determination that the power consumption of the set of LEDs        satisfies the power threshold, determining whether a light        emission duration of the set of LEDs satisfies a duration        threshold; and deactivating the set of LEDs in response to a        determination that the light emission duration satisfies the        duration threshold.    -   A.10. The device of any of embodiments A.7 to A.9, wherein the        set of LEDs is positioned below a transverse plane of the        attachment body.    -   A.11. The device of any of embodiments A.7 to A.10, wherein the        attachment body is fixed to the casing at a plurality of        attachment positions.    -   A.12. The device of any of embodiments A.7 to A.11, wherein the        attachment body is fixed to the casing by at least one of a        threaded member, a snap fastener member, or an adhesive.    -   A.13. The device of any of embodiments A.7 to A.13, wherein: the        aperture is a first aperture; the casing comprises a plurality        of apertures; the plurality of apertures is greater than three        apertures; each respective aperture of the plurality of        apertures is aligned with at least one sensor of a plurality of        sensors of the head-mounted display.    -   A.14. A device comprising: a casing comprising a cavity, wherein        a lens of a head-mounted display is positioned inside the cavity        when the device is attached to the head-mounted display; and an        attachment body, wherein a posterior end of the attachment is        fixed to an anterior end of the casing, the attachment body        comprising: a set of light-emitting diodes (LEDs), wherein the        set of LEDs is attached to the posterior end of the attachment        body and is directed towards the anterior end of the casing; a        first circuitry that is configured to control light emission of        the set of LEDs; and a second circuitry that is in electrical        communication with the set of LEDs, wherein the second circuitry        is configured to deactivate the set of LEDs independently of the        first circuitry.    -   A.15. The device of embodiment A.14, wherein the second        circuitry is configured to deactivate the set of LEDs in        response to the set of LEDs being activated for a duration        threshold.    -   A.16. The device of any of embodiments A.14 to A.15, wherein:        the attachment body comprises an antenna; the first circuitry is        in communication with the antenna; and the second circuitry is        not in communication with the antenna.    -   A.17. The device of embodiment A.16, wherein the first circuitry        comprises: a memory; and a set of processors, wherein the memory        stores program instructions that, when executed by the set of        processors, cause the set of processors to perform operations        comprising: detecting that the second circuitry has deactivated        the set of LEDs; and sending a wireless message to a computing        device indicating that the second circuitry has deactivated the        set of LEDs.    -   A.18. The device of any of embodiments A.14 to A.17, wherein the        set of LEDs is configured to emit bleaching light on a retinal        surface area such that at least one arc of a region illuminated        by the bleaching light is greater than two degrees.    -   A.19. The device of any of embodiments A.14 to A.18, wherein:        the set of LEDs is a first set of LEDs; a second set of LEDs is        directed to a second lens of the head-mounted display; and the        attachment body comprises a third circuitry that is in        electrical communication with the second set of LEDs, wherein        the second circuitry is configured to deactivate the set of LEDs        independently of the first circuitry and the second circuitry.    -   A.20. The device of embodiment A.20, wherein the set of LEDs is        movable along a horizontal direction of the attachment body or        vertical direction of the attachment body.    -   B.1. A system comprising: an attachment body fixed to an        anterior end of a casing by a coupling, the attachment body        comprising: a set of light-emitting diodes (LEDs), wherein the        set of LEDs is attached to posterior end of the attachment body        and is directed towards the anterior end of the casing; and a        circuitry, the circuitry comprising a first sub-circuitry and a        second sub-circuitry, wherein the first sub-circuitry is        configured to control light emission of the set of LEDs, and        wherein the second sub-circuitry is configured to deactivate the        set of LEDs independently of the first sub-circuitry; a set of        processors; and a memory storing program instructions that, when        executed by the set of processors, causes the set of processors        to perform operations comprising: emitting light at a target        intensity using the set of light-emitting diodes (LEDs); and        receiving measurements of eye responses from a head-mounted        display after the emission of the light at the target intensity.    -   B.2. The system of embodiment B.1, the operations further        comprising: detecting that the set of LEDs has stopped emitting        the light at the target intensity; and receiving, from the        circuitry, a signal indicating the light at the target intensity        is not being emitted within 5 milliseconds after detecting that        the set of LEDs have stopped emitting the light at the target        intensity.    -   B.3. The system of any of embodiments B.1 to B.2, the operations        further comprising: obtaining a retina position based on a        measurement of the eye; selecting the set of LEDs by determining        an illumination position that will center light within a first        degree range of the eye, wherein emitting the light at the        target intensity comprises illuminating a retinal surface area        such that at least one arc of the retinal surface area is        greater than two degrees.    -   B.4. The system of any of embodiments B.1 to B.3, the operations        further comprising: determining a pupil radius based on the        measurements of eye responses; determining a target brightness        based on the pupil radius, wherein the target brightness is        negatively correlated with the pupil radius; updating a        brightness of a stimulus displayed on a lens of the head-mounted        display with the target brightness.    -   B.5. The system of any of embodiments B.1 to B.4, wherein: the        set of LEDs is a first set of LEDs; a second set of LEDs is        directed to a second lens of the head-mounted display; and        emitting the light at the target intensity comprises emitting        the light using the first set of LEDs without emitting light        using the second set of LEDs.    -   C.1. A system comprising: an HMD comprising a transparent lens        and a memory storing program instructions that, when executed by        a set of processors of the HMD, performs operations comprising:        determining whether a set of light-activating criteria is        satisfied based on a set of images collected by an        interior-facing camera of the HMD by detecting image regions        indicating a human eye based on the set of images; and        wirelessly transmitting a set of activating messages in response        to a determination that the set of light-activating criteria is        satisfied; and an accessory configured to attach to the HMD and        comprising a set of light-emitting diodes (LEDs) to emit a        bleaching light having a bleaching intensity that is visible        through the transparent lens of the HMD, wherein a circuitry of        the accessory stores program instructions that, when executed by        the circuitry, performs operations comprising: receiving the set        of activating messages via a wireless receiver of the accessory;        and in response to receiving the set of activating messages,        activating the set of LEDs to emit the light at the bleaching        intensity through the transparent lens of the HMD.    -   C.2. The system of any of embodiments C.1 to C.2, wherein: the        HMD comprises exterior-facing cameras on a front end of the HMD;        and the accessory comprises: a casing comprising a cavity that        encompasses the transparent lens of the HMD when the casing is        attached to the HMD, wherein a plurality of apertures are        aligned with the exterior-facing cameras of the HMD when the        casing is attached to the HMD; and an accessory body, wherein a        back end of the accessory body is fixed to a front end of the        casing, wherein: the set of LEDs is attached to a back end of        the accessory body and is directed towards the transparent lens;        the circuitry is at least partially enclosed within the        accessory body; and the circuitry comprises the wireless        receiver.    -   C.3. A system comprising: a head-mounted display (HMD)        comprising a memory storing program instructions that, when        executed by a set of processors of the HMD, performs operations        comprising: determining whether a set of criteria is satisfied        based on eye-related readings collected by a camera the HMD; and        wirelessly transmitting a set of messages in response to a        determination that the set of criteria is satisfied; and an        attachment comprising a set of light-emitting diodes (LEDs) to        emit a light at a bleaching intensity that passes through a lens        of the HMD, wherein the attachment stores program instructions        that, when executed by the attachment, performs operations        comprising activating the set of LEDs to emit the light at the        bleaching intensity in response to receiving the set of        messages.    -   C.4. The system of embodiment C.3, wherein: the eye-related        readings comprises a set of images; and determining whether the        set of criteria is satisfied comprises: detecting an eye of the        set of images; determining a gaze location of the eye based on        the set of images; determining that the gaze location of the eye        is focused in a target region, wherein determining that the set        of criteria is satisfied comprises determining that the gaze        location is focused in the target region.    -   C.5. The system of any of embodiments C.3 to C.4, wherein: the        eye-related readings are first eye-related readings; the set of        messages is a first set of messages; and the operations further        comprising: determining a first pupil size based on the first        eye-related readings; generating or updating the first set of        messages to comprise a first set of parameter that causes the        set of LEDs to emit light at a first brightness based on a        determination that the first pupil size is less than a size        threshold; obtaining second eye-related readings via the camera;        determining a second pupil size based on the second eye-related        readings; generating or updating a second set of messages to        comprise a second set of parameters that causes the set of LEDs        to emit light at a second brightness based on a determination        that the second pupil size is greater than the size threshold,        wherein the second brightness is less than the first brightness;        and transmitting the second set of messages to the attachment.    -   C.6. The system of embodiment C.5, wherein the size threshold is        less than or equal to 5 millimeters.    -   C.7. The system of any of embodiments C.3 to C.6, wherein the        set of messages is a first set of messages, the operations        further comprising: determining a pupil size based on the        eye-related readings; generating or updating the first set of        messages to comprise information that causes the set of LEDs to        emit light at a first brightness based on a determination that        the pupil size is less than a size threshold; receiving, with        the HMD, a user-provided value indicating that a brightness was        too long; adjusting a configuration parameter; and generating or        updating a second set of messages based on the configuration        parameter, wherein the second set of messages causes the set of        LEDs to emit light at a second brightness that is less than the        first brightness.    -   C.8. The system of any of embodiments C.3 to C.7, wherein: the        set of messages causes the attachment to determine a luminosity;        and the attachment stores program instructions to determine a        current based on the luminosity.    -   C.9. The system of any of embodiments C.3 to C.8, the operations        further comprising receiving a voice-activated stimulus, wherein        determining whether the set of criteria is satisfied comprises        initiating a testing operation that causes the attachment to        determine whether the set of criteria is satisfied in response        to receiving the voice-activated stimulus.    -   C.10. The system of any of embodiments C.3 to C.9, the        operations further comprising: receiving a set of images based        on a set of exterior-facing cameras of the HMD; detected a        target motion or a target shape based on the set of images; and        determining whether a set of visual stimulus criteria is        satisfied based on the target motion or the target shape,        wherein determining whether the set of criteria is satisfied        comprises initiating a testing operation that causes the        attachment to determine whether the set of criteria is satisfied        in response to determining that the set of visual stimulus        criteria is satisfied.    -   C.11. The system of any of embodiments C.3 to C.10, wherein: the        eye-related readings comprises a set of images; and determining        whether the set of criteria is satisfied comprises: detecting an        image region indicating an eye by providing the set of images to        a set of classifiers; determining a pupil size of the eye based        on the image region; determining whether the pupil size        satisfies a minimum threshold, wherein determining that the set        of criteria is satisfied comprises determining that the pupil        size satisfies the minimum threshold.    -   C.12. A method comprising: determining, with a head-mounted        display (HMD), whether a set of criteria is satisfied based on        eye-related readings collected by a sensor the HMD; wirelessly        transmitting, with the HMD, a set of messages in response to a        determination that the set of criteria is satisfied; and        activating, with an attachment, a set of LEDs of the attachment        to emit a bleaching light that passes through a lens of the HMD        in response to receiving the set of messages.    -   C.13. The method of embodiment C.12, wherein activating the set        of LEDs comprises activating the set of LEDs using a first        circuitry of the attachment, further comprising: deactivating,        with a second circuitry of the attachment, the set of LEDs in        response to the set of LEDs being activated for a duration        threshold, wherein the first circuitry is different from the        second circuitry; and sending a warning message to the HMD        indicating that the second circuitry has deactivated the set of        LEDs.    -   C.14. The method of any of embodiments C.12 to C.13, further        comprising: retrieving, from a memory of the HMD, configuration        parameters that sets or updates LED emission durations;        determining a subset of the configuration parameters associated        with LED emission durations that exceed a duration threshold;        and visually indicating the subset of the configuration        parameters on a display device.    -   C.15. The method of any of embodiments C.12 to C.14, further        comprising: displaying a visual stimulus on the lens;        determining a gaze location based on the eye-related readings;        and determining whether the gaze location is within a threshold        range of the visual stimulus, wherein transmitting the set of        messages comprises transmitting the set of messages in response        to a determination that the gaze location is within the        threshold range of the visual stimulus.    -   C.16. The method of embodiment C.15, wherein the visual stimulus        is a first visual stimulus, the gaze location is a first gaze        location, further comprising: displaying a sequence of visual        stimuli on the lens, wherein the sequence of visual stimuli        comprises the first visual stimulus; and for each respective        stimulus of the sequence of visual stimuli: obtaining a        respective set of images of an eye with the sensor; determining        a respective gaze location based on the respective set of        images; determining whether the respective gaze location is        within a respective threshold range of the respective stimulus;        and activating the set of LEDs in response to a determination        that the respective gaze location is within the respective        threshold range of the respective stimulus.    -   C.17. The method of any of embodiments C.12 to C.16, wherein        activating the set of LEDs comprises activating the set of LEDs        during a first duration, further comprising: collecting a set of        eye-related readings with the sensor during a data collection        period after the set of LEDs is activated; determining a set of        eye-related information based on the set of eye-related        readings, wherein the set of eye-related information indicates        values over the data collection period; determining, with the        HMD, whether a set of time-based criteria is satisfied based on        the set of eye-related information; and transmitting a second        set of messages to a receiver of the attachment that causes the        set of LEDs to emit light during a second duration based on a        determination that the set of time-based criteria is not        satisfied.    -   C.18. The method of embodiment C.17, wherein the eye-related        readings is a first set of eye-related readings, further        comprising: collecting second eye-related readings with the        sensor during a second data collection period after the second        duration; determining a second set of eye-related information        based on the second eye-related readings, wherein the second set        of eye-related information indicates changes over the second        data collection period; determining, with the HMD, whether the        set of time-based criteria is satisfied based on the second set        of eye-related information; and presenting a visual stimulus on        the lens in response to a determination that the set of        time-based criteria is satisfied.    -   C.19. The method of any of embodiments C.12 to C.18, further        comprising obtaining, with the HMD, a test category indicating a        test configuration, wherein transmitting the set of messages        comprises transmitting parameters indicating an LED subset of        the set of LEDs to activate based on the test category.    -   C.20. The method of embodiment C.19, wherein the LED subset of        the set of LEDs emit light at a first wavelength that is        different a second wavelength emitted by an LED of the set of        LEDs not included in the LED subset.

What is claimed is:
 1. A head-mounted display and accessory system inwhich the accessory emits bleaching light through the head-mounteddisplay to bleach photoreceptors for dark adaptation testing, the systemcomprising: a head-mounted display comprising transparent lenses andexterior-facing cameras on a front end of the head-mounted display andadjacent to the transparent lenses, wherein at least one pair of camerasof the exterior-facing cameras are on opposite sides of a vertical planeof the head-mounted display; and an accessory device positioned on afront end of the head-mounted display, the accessory device comprising:a light shield casing comprising: a cavity that encompasses thetransparent lenses of the head-mounted display when the accessory deviceis attached to the head-mounted display, wherein the light shield casingshields the cavity from light from an environment of the head-mounteddisplay when the accessory device is attached to the head-mounteddisplay; and a plurality of apertures aligned with the exterior-facingcameras; and an attachment body fixed to a front end of the light shieldcasing, the attachment body comprising: a set of light-emitting diodes(LEDs) to emit light at a bleaching intensity, wherein the set of LEDsis attached to a back end of the attachment body and is directed towardsat least one lens of the transparent lens, and wherein light emitted bythe set of LEDs is visible through at least one lens of the transparentlenses; and a circuitry that is at least partially enclosed within theattachment body and is in electrical communication with the set of LEDs,wherein the circuitry is configured to control the light emission of theset of LEDs.
 2. The system of claim 1, wherein the circuitry is acontroller circuitry, and wherein the attachment body further comprisesa safety circuitry that is in electrical communication with the set ofLEDs, wherein the safety circuitry comprises a relay or microcontrollerto deactivate the set of light-emitting diodes independently of thecontroller circuitry.
 3. The system of claim 1, wherein the controlleris configured to perform operations comprising: emitting a first lightat a first intensity with the set of LEDs in response to receiving afirst command via an interface of the circuitry, wherein the firstintensity is not a bleaching intensity; and emitting a second light at asecond intensity with the set of LEDs in response to receiving a secondcommand via the interface, wherein the second intensity is a bleachingintensity.
 4. The system of claim 1, wherein the circuitry performsoperations comprising emitting a first light at a first intensity withthe set of LEDs in response to receiving a first command via aninterface of the circuitry, wherein the first light is emittedconcurrently with a light emitted by the head-mounted display.
 5. Thesystem of claim 1, further comprising: a filter coupling; and a neutraldensity filter fixed to the filter coupling, wherein the set of LEDs isdirected towards the neutral density filter such that the light emittedby the set of LEDs passes through the neutral density filter.
 6. Thesystem of claim 1, wherein the plurality of apertures comprises at leastsix apertures, and wherein at least one aperture of the plurality ofapertures is aligned with a microphone.
 7. A device comprising: a casingcomprising a cavity, wherein a lens of a head-mounted display ispositioned inside the cavity when the device is attached to thehead-mounted display, and wherein an aperture of the casing is alignedwith an exterior-facing camera of the head-mounted display; and anattachment body, wherein a posterior end of the attachment body is fixedto an anterior end of the casing, the attachment body comprising: a setof light-emitting diodes (LEDs), wherein the set of LEDs is attached tothe posterior end of the attachment body and is directed towards thelens; and a circuitry that is configured to control light emission ofthe set of LEDs.
 8. The device of claim 7, wherein: the lens is a firstlens; the attachment body comprises a midsection that is bisected by asagittal plane of the attachment body; the midsection is longer alongthe sagittal plane of the attachment body in comparison to a leftsection of the attachment body or a right section of the attachmentbody; the set of LEDs is a first set of LEDs; a second set of LEDs isattached to the posterior end of the attachment body and is directedtowards a second lens of the head-mounted display; the first set of LEDsand the second set of LEDs are substantially symmetric about thesagittal plane; and a distance between the first set of LEDs and thesecond set of LEDs is greater than or equal to 40 millimeters.
 9. Thedevice of claim 7, wherein the circuitry is a first circuitry, andwherein a second circuitry comprises a microcontroller configured toperform operations comprising: determining whether a power consumptionof the set of LEDs satisfies a power threshold; in response to adetermination that the power consumption of the set of LEDs satisfiesthe power threshold, determining whether a light emission duration ofthe set of LEDs satisfies a duration threshold; and deactivating the setof LEDs in response to a determination that the light emission durationsatisfies the duration threshold.
 10. The device of claim 7, wherein theset of LEDs is positioned below a transverse plane of the attachmentbody.
 11. The device of claim 7, wherein the attachment body is fixed tothe casing at a plurality of attachment positions.
 12. The device ofclaim 7, wherein the attachment body is fixed to the casing by at leastone of a threaded member, a snap fastener member, or an adhesive. 13.The device of claim 7, wherein: the aperture is a first aperture; thecasing comprises a plurality of apertures; the plurality of apertures isgreater than three apertures; each respective aperture of the pluralityof apertures is aligned with at least one sensor of a plurality ofsensors of the head-mounted display.
 14. A device comprising: a casingcomprising a cavity, wherein a lens of a head-mounted display ispositioned inside the cavity when the device is attached to thehead-mounted display; and an attachment body, wherein a posterior end ofthe attachment is fixed to an anterior end of the casing, the attachmentbody comprising: a set of light-emitting diodes (LEDs), wherein the setof LEDs is attached to the posterior end of the attachment body and isdirected towards the anterior end of the casing; a first circuitry thatis configured to control light emission of the set of LEDs; and a secondcircuitry that is in electrical communication with the set of LEDs,wherein the second circuitry is configured to deactivate the set of LEDsindependently of the first circuitry.
 15. The device of claim 14,wherein the second circuitry is configured to deactivate the set of LEDsin response to the set of LEDs being activated for a duration threshold.16. The device of claim 14, wherein: the attachment body comprises anantenna; the first circuitry is in communication with the antenna; andthe second circuitry is not in communication with the antenna.
 17. Thedevice of claim 16, wherein the first circuitry comprises: a memory; anda set of processors, wherein the memory stores program instructionsthat, when executed by the set of processors, cause the set ofprocessors to perform operations comprising: detecting that the secondcircuitry has deactivated the set of LEDs; and sending a wirelessmessage to a computing device indicating that the second circuitry hasdeactivated the set of LEDs.
 18. The device of claim 14, wherein the setof LEDs is configured to emit bleaching light on a retinal surface areasuch that at least one arc of a region illuminated by the bleachinglight is greater than two degrees.
 19. The device of claim 14, wherein:the set of LEDs is a first set of LEDs; a second set of LEDs is directedto a second lens of the head-mounted display; and the attachment bodycomprises a third circuitry that is in electrical communication with thesecond set of LEDs, wherein the second circuitry is configured todeactivate the set of LEDs independently of the first circuitry and thesecond circuitry.
 20. The device of claim 19, wherein the set of LEDs ismovable along a horizontal direction of the attachment body or verticaldirection of the attachment body.